How can I get there? Disorientation and motion sickness ...

How can I get there?Disorientation and motion

sickness effects depending on thevirtual reality navigation

technique

Master thesis report

Marc Domenech Lopez

Aalborg UniversityArchitecture, Design and Mediatechnology

Copyright c© Aalborg University 2019

In this project Microsoft Visual Studio has been used as main integrated developmentenvironment. Additionally, the Aardvark Platform, developed by VRVis has also beenused for the development of this project.

Architecture, Design and MediaTechnology

Aalborg Universityhttp://www.aau.dk

Title:How can I get there? Disorientation andmotion sickness effects depending onthe virtual reality navigation technique

Theme:Master’s Thesis

Project Period:Spring Semester 2020

Project Group:MTA201043

Participant(s):Marc Domenech Lopez

Supervisor(s):Martin Kraus

Copies: 1

Page Numbers: 45

Date of Completion:May 28, 2020

Abstract:

Navigation in virtual reality is presentin every application. Users needto move around the virtual environ-ment in a user-friendly, intuitive andmotion-sickness free way. Nonethe-less, the diverse applications offeredby this technology result in differentvirtual environments with different re-quirements in each case. To fulfillthese requirements and give the usera better experience the selection of anappropriate technique is important inevery case. For this reason, there isnot a locomotion technique free of dis-orientation and motion sickness symp-toms in different environments. Withthe aim of finding the appropriatenavigation method in big virtual en-vironments, three methods are com-pared against each other: teleporta-tion, World in Miniature (WIM) anddrone navigation. A task of navigatingto a specified target and then findinganother one suggested that the WIMtechnique could reduce motion sick-ness and disorientation in these kindof environments.

The content of this report is freely available, but publication (with reference) may only be pursued due to

agreement with the author.

http://www.aau.dk

Architecture, Design and Mediatechnology

Aalborg Universitethttp://www.aau.dk

Titel:How can I get there? Disorientation andmotion sickness effects depending onthe virtual reality navigation technique

Tema:Kandidatespeciale

Projektperiode:10. Semester

Projektgruppe:MTA201043

Deltager(e):Marc Domenech Lopez

Vejleder(e):Martin Kraus

Oplagstal: 1

Sidetal: 45

Afleveringsdato:28. maj 2020

Abstract:

Navigation in virtual reality is pre-sent in every application. Users needto move around the virtual environ-ment in a user-friendly, intuitive andmotion-sickness free way. Nonetheless,the diverse applications offered by thistechnology result in different virtualenvironments with different require-ments in each case. To fulfill theserequirements and give the user a betterexperience the selection of an appro-priate technique is important in everycase. For this reason, there is not a lo-comotion technique free of disorienta-tion and motion sickness symptoms indifferent environments. With the aimof finding the appropriate navigationmethod in big virtual environments,three methods are compared againsteach other: teleportation, World in Mi-niature (WIM) and drone navigation.A task of navigating to a specified tar-get and then finding another one sug-gested that the WIM technique couldreduce motion sickness and disorien-tation in these kind of environments.

Rapportens indhold er frit tilgængeligt, men offentliggørelse (med kildeangivelse) må kun ske efter aftale med

forfatterne.

http://www.aau.dk

Contents

1 Introduction 1

2 State of the Art 3

3 Design 93.1 The navigation techniques . . . . . . . . . . . . . . . . . . . . . . . . . 93.2 The user evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

4 Implementation of the locomotion techniques 154.1 Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154.2 Real users . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154.3 Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164.4 Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

4.4.1 General implementation . . . . . . . . . . . . . . . . . . . . . . 174.4.2 Teleportation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194.4.3 Drone navigation . . . . . . . . . . . . . . . . . . . . . . . . . . 204.4.4 World in Miniature . . . . . . . . . . . . . . . . . . . . . . . . . 21

5 Evaluation 255.1 Participants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255.2 Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255.3 Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265.4 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

6 Discussion 31

7 Conclusion and Future Work 33

Bibliography 35

A Appendix 37A.1 Logs of the implementation . . . . . . . . . . . . . . . . . . . . . . . . 37

vii

viii Contents

A.1.1 Week 1(10th - 14th February) . . . . . . . . . . . . . . . . . . . 37A.1.2 Week 2(17th - 21st February) . . . . . . . . . . . . . . . . . . . 37A.1.3 Week 3(24th - 28th February) . . . . . . . . . . . . . . . . . . . 37A.1.4 Week 4(2nd - 6th March) . . . . . . . . . . . . . . . . . . . . . 38A.1.5 Week 5(9th - 13th March) . . . . . . . . . . . . . . . . . . . . . 38A.1.6 Week 6(16th - 20th March) . . . . . . . . . . . . . . . . . . . . 38A.1.7 Week 7(23rd - 27th March) . . . . . . . . . . . . . . . . . . . . 39A.1.8 Week 8(30th March - 3rd April) . . . . . . . . . . . . . . . . . . 39A.1.9 Week 9(6th - 10th April) . . . . . . . . . . . . . . . . . . . . . . 39A.1.10 Week 10(13th - 17th April) . . . . . . . . . . . . . . . . . . . . 40A.1.11 Week 11(20th - 24th April) . . . . . . . . . . . . . . . . . . . . 40A.1.12 Week 12(27th - 30th April) . . . . . . . . . . . . . . . . . . . . 40A.1.13 Week 13(4th - 8th May) . . . . . . . . . . . . . . . . . . . . . . 41A.1.14 Week 14(11th - 13th May) . . . . . . . . . . . . . . . . . . . . . 41

A.2 Demographics Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . 41A.3 Likert Questionnaire . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42A.4 Simulator Sickness Questionnaire . . . . . . . . . . . . . . . . . . . . . 43A.5 Preference over techniques questionnaire . . . . . . . . . . . . . . . . 44

Chapter 1

Introduction

Virtual reality (VR) users have increased significantly over the last few years. Thisis, in fact, thanks to the introduction of low-cost head mounted displays, such asthe Oculus Rift, the HTC Vive and the Google Cardboard [19], transforming VRinto a widely-accessible and popular technology [2].

From a scientific point of view, VR has undergone a major technological revival,producing new interaction metaphors, design and tools [2]. Consequently, users’experiences have been affected, and the number of VR and Human-Computer In-teraction (HCI) studies has drastically increased.

Among the common topics of investigation there is navigation, being also a com-mon topic of discussion in VR-related forum threads and tech articles. Bloggers,tech journalists or forum users claim the best way to move around in VR is still notfigured out [4].

VR navigation has suffered this technological revival. The navigation componentis present in all VR applications; therefore, it has brought interest to scientists todevelop and study user-friendly navigation techniques in virtual environments [9].

In pursuit of contributing to the VR community, this study compares three dif-ferent navigation techniques in collaboration with the research company VRVis.The aim of the study is to discover an intuitive navigation method that reducesmotion sickness and disorientation.

The research company VRVis (VRVis Zentrum für Virtual Reality und VisualisierungForschungs-GmbH) conducts innovatice research and develops projects in cooper-ation with industries and universities [23]. The company covers a wide range ofdata types and applications all of them applied to the field of visual computing.

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Chapter 2

State of the Art

VR navigation, also known as VR Locomotion, is one of the core tasks to be per-formed in a virtual environment. In order to navigate successfully, the spatialknowledge gained about the environment is used by users to plan the next move-ment [21]. However, some of the users often experience difficulties when traveling,which usually can lead to disorientation [7], because of the extra degrees of free-dom within a virtual environment, or cybersickness [17] (also known as VR sick-ness), because they require a mismatch between the sensory information receivedby the visual system and the vestibular system of users.

Due to the challenges presented by the current navigation techniques, a defini-tive way of traveling that makes navigation lightweight so that users can focus onmore important tasks is yet to be implemented [7]. There are several studies col-lecting the different techniques that have been studied so far [2, 7], dividing theminto more general categories in order to select an appropriate technique dependingon the real and virtual environment.

Bowman et al. [7] subdivided the navigation into the motor component calledtravel and the cognitive component called wayfinding. On top of this subdivision,Bowman et al. also divided the navigation tasks into the following three categories:

Exploration: navigation with no explicit target.

Search tasks: involve moving to a particular target location.

Maneuvering: characterized by short-range, high-precision movement that areused to place the viewpoint at a more advantageous location for performing aparticular task.

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4 Chapter 2. State of the Art

Lastly, they also divided the travel interaction techniques into five differentcategories: physical movement, manual viewpoint manipulation, steering, target-based travel and route planning.

With all these categorizations, Bowman et al. were able to conduct different com-parisons of techniques, that then served as a basis for design guidelines [5, 6, 7, 8].Another group of scientists that compared among all the studied techniques wereBoletsis et al. [2] that explored the VR locomotion techniques studied from 2014-2017 in order to identify research gaps and to construct new conceptual knowl-edge for future VR locomotion related work. The result of the 92 articles checkedresulted in a different group formation described in Figure 2.1, which shows thedifferent categories, from general to specific, in which each technique could be partof.

Figure 2.1: VR locomotion typology extracted from Boletsis et al. study

Boletsis et al. counted the number of instances each technique appeared in thestudies analyzed. Walking-in-place and controller-based locomotion techniquesresulted to be the most utilized techniques, each of them corresponding to twodifferent interaction techniques: physical vs. artificial. For the sake of simplicity,the naming of controller-based locomotion technique used by Boletsis et al. willbe replaced by steering technique, which was used by Bowman et al. The reasonis that controller-based can be broad, and lead to confusion because, for example,teleportation also uses controllers.

Another observation is that teleportation is not studied or utilised as much. In-teresting because teleportation is provided in many professional applications andpublic installations. For this reason, teleportation was expected to be studied inmuch more depth, representing a clear gap encouraging future studies to taketeleportation into account.

5

Stoakley et al. [22] and Pausch et al. [20] presented the World-in-Miniature (WIM)concept in their studies, a graphical representation of the virtual environment thatallows the user to change the viewpoint and location through moving a virtualrepresentation of oneself in the WIM. Figure 2.2 corresponds to a representationof how the WIM was presented in Stoakley et al. study, in which users had tomanipulate objects in the virtual environment.

Figure 2.2: World in Miniature layout used in Stoakley et al. study

Berger et al. [1] then proved a gain of spatial knowledge by providing an overviewof the environment and a clear understanding of the location of the landmarksversus the position of the user. In addition, motion sickness was also compared tocontinuous motion and teleportation in this paper.

Rating Motion sickness Spatial knowledgeBest WIM WIM

Teleport TeleportWorst Continuous motion Continuous motion

Table 2.1: Results obtained in Berger et al. study

6 Chapter 2. State of the Art

Table 2.1 shows the results obtained, proving that WIM can be a promising candi-date to navigate in a virtual environment over continuous motion or teleportation,two common navigation techniques nowadays.

The three locomotion techniques were compared in three different environments tocover different levels of difficulty. Furthermore, three different distances betweenthe start and end point were also studied to form paths. The largest distance cov-ered was 45 metres, which is a smaller distance than our environment. This way,it is interesting to study if the same results apply in bigger virtual environments.

Steering locomotion techniques are one of the most studied techniques [1, 11, 12].Despite the fact of the user being stationary and using a controller, these tech-niques can result cognitively intense and can also lead to VR sickness [2]. LaViola[16] described the two most important body parts that are associated with cyber-sickness before discussing the three main theories that cause this feeling of sicknessin order to alleviate it. The most accepted theory is the sensory conflict theory andit is based on the discrepancies between the two senses involved in cybersickness(the vestibular sense and the visual sense). This sensory conflict arise when thesensory information is not the stimulus that the subject expected based on theirexperience. Figure 2.3 describes the possible conflict that can be generated if thereis a mismatch between the vestibular and the visual system.

Figure 2.3: Sensory conflict between the vestibular and visual senseSource: [18]

Other factors that can also contribute to cybersickness can be related to display andtechnology issues, like lagging or flickering, or individual factors such as gender,age or illness.

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It is surprising, though, that even with all the studies proving that steering lo-comotion techniques tend to cause motion sickness, VR users prefer to use it any-way. Kraus et al. [14] discussed the possible factors that have lead over 90% ofVR players of Rec Room, a multiplayer video game, moved over from teleporta-tion to joystick-based navigation. Preference factors were the age of the averageuser (young users are less susceptible to cybersickness), immersion, physical er-gonomics and pleasure.

Innovative techniques are continuously being studied against the most commonones due to the fact that a definitive locomotion technique is yet to be found. Jacobet al. [11] presented a new locomotion technique based on nodes placed 1 to 1.5meters from each other and which users moves rapidly towards them if they arelooking at them and trigger a button. This new technique offered better resultsas regards to motion sickness when comparing it to teleportation and continuouslocomotion in a study which users had to move from one point to another usingthe three different techniques.

Chapter 3

Design

In this section the selection and design of the different locomotion techniquesamong all the possible ones is discussed. Three navigation techniques have beenselected to be compared against each other.

The idea when deciding the techniques was that each had to be different betweeneach other so that users do not get confused when using any of the techniques.Furthermore, the fact of using a big virtual environment had also to be taken intoaccount when deciding. If a user is presented with a big virtual environment andthe only navigation technique is Walking on Point, the experience might resultnegative because the user will have to walk long times to mover around.

Combination of different locomotion techniques has also been applied, in the ex-tent possible. In addition, the interaction has to be intuitive, as it is valued by theusers and created a better experience.

The second section of this chapter is related to the design of the evaluation. Themain factors to measure in the study are disorientation and cybersickness. A partfrom that, the interaction with the interface should be intuitive and natural so thatthe user has a positive experience.

3.1 The navigation techniques

Limitations like not having enough physical space on site or working with a rel-atively big virtual environment lead to the rejection of physical interaction tech-niques. This way, steering and teleportation based techniques were left to be usedin the study.

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10 Chapter 3. Design

The hardware used during the evaluation is an important factor. In this study,an intuitive and natural way to navigate should be offered to the users so that theycan focus on the main part of their measurements or studies. Ferreira et al. [21]compared a traditional desktop setup with a head mount set when carrying nav-igation search tasks. The results of the study were that users felt the head mountset application to be more intuitive and natural even though their performance wasbetter using the desktop setup.

In order to have a helpful study for the virtual reality community, at least twoor three different and innovative navigation techniques had to be compared. Oneof the techniques should be one of the most used currently to discover if userswould rather use a different technique or not.

For this reason, teleportation is one of the locomotion techniques of the study.The point & teleport technique has been designed without innovations. Users usea laser to point a place in the scene and the intersection point between the laserand the surface will be the final destination when the user triggers a button. Fig-ure 3.1 illustrates the point & teleport technique, which is one of the most commonlocomotion techniques in the virtual reality community.

Figure 3.1: Point & teleport illustration

The second technique has not been tested in previous studies because it is an adap-tation of remote-controlling a drone using a camera on the drone in real life. Theidea is to bring this method of navigating to virtual reality and use the drone toexplore the areas of interest through the screen that displays the drone’s view.

This technique could be included in the steering-based technique group, referringto Figure 2.1. The fact of directing the drone using the orientation of the controller

3.1. The navigation techniques 11

can help users to easily learn how to use this technique. Furthermore, to avoid theconflict between the vestibular sense and the visual sense that causes cybersick-ness, users do not move. Instead, the drone moves for them and there is a screenclose to the user that displays the drone’s view. Figure 3.2 depicts a sketch of whatthe drone navigation technique would look like. In the figure, the user can see thedrone’s trajectory through the screen, which is attached to the controller’s position.

Figure 3.2: Sketch of the drone navigation idea

This idea emerged by trying to eliminate the continuous motion, factor that causescybersickness, but still using a steering interaction, which is widely used in the vir-tual reality community and computer games in general. To eliminate continuousmotion, navigation methods that use a non-moving environment around the userare the solution. In non-moving environment methods there is a virtual screenthat displays the view from a moving camera. Another method in this regard is tomake users think they are inside a vehicle so they have a similar feeling to whenthey are driving.

The last technique of the study is the World in Miniature (WIM) navigation method.This method was chosen due to the positive results that had proved in smaller en-vironments in previous studies, encouraging further experiments in different con-ditions to see if they also apply. Boletsis et al. implemented a World-In-Miniatureenvironment proving that this method of navigation reduces cybersickness anddisorientation [22, 1].

Furthermore, having a mini-map of the whole virtual environment should helpusers gain spatial knowledge, specially in big virtual environments. The environ-ment can be seen in a smaller scale and, therefore, more landmarks can be used toorient users. A sketch of the WIM idea is presented in Figure 3.3, in which differ-ent landmarks are shown in both the virtual world and the mini map overview.

12 Chapter 3. Design

Figure 3.3: Sketch of the World in Miniature idea

Another aspect added in this technique is the indication of the user’s current posi-tion in the real world. When changing position in the mini-map, users are able tosee where in the real world they would go at any time. This indication helps usersgain spatial knowledge of the scene and in consequence, feel more oriented.

3.2 The user evaluation

The two main constraints that have to be accomplished by the evaluation are todetermine if users feel disoriented or suffer cybersickness while using the differenttechniques implemented as well as to discover which is the most effective tech-nique in this regard.

For this reason, studies that measure these parameters have been taken accountto explore what kind of evaluation the scientists conducted. Langbehn et al. [15]and Boletsis et al. [3] both compared different locomotion techniques between eachother with the aim of documenting and guiding the design process of new distin-guished locomotion techniques. Disorientation and motion sickness were some ofthe aspects that were measured in the studies.

Due to the similarity of the objectives of their studies and this one, the evalua-tion design is inspirational. Langbehn et al. participants had to navigate to severaltargets, visualized as color semi-transparent pillars. In addition to that, partici-pants had to fulfill a pointing task that consisted of pointing at the position of thetargets after reaching the last target, to analyze the effects of the different locomo-tion techniques on cognitive map building. Lastly, they had to draw a 2D map ofthe virtual environment and place the set of furniture and objects of the scene asthey remembered.

Similarly to Langbehn et al.’s study, Boletsis et al. was based on a city with dif-ferent assets and interesting locations that users had to navigate through whilstusing the different navigation techniques. In this study, the task for the users wasto locate four different locations in a 15 minute time frame.

3.2. The user evaluation 13

To measure the feeling of motion sickness, participants answered a questionnairein both studies.

Figure 3.4: Maps with landmarks of Langbehn et al.’s study (left) and Boletsis et al.’s study (right)

It is clear then, that using landmarks in the virtual environment to measure theorientation of the participants can be considered as a method. In order to measurethe feeling of motion sickness, verbal feedback and questionnaires is a standardway to do so. There are standardized questionnaires that have been used in severalstudies.

Chapter 4

Implementation of the locomotiontechniques

This section describes the implementation of the three different techniques usedin the experiment: teleportation, drone navigation and World in Miniature (WIM),consisting of a mini map.

Before going into a technical point of view, requirements, real users and toolsneeded for the study, which apply equally for all the techniques.

4.1 Requirements

The main purpose of this study, as mentioned in previous sections, is to be ableto move around the scene by means of different techniques, in order to discoverwhich one is more convenient and comfortable in similar virtual environments.

The three techniques can be performed using one controller. With the main con-troller, the user will be able to change to a different position in the environmentand to a different orientation.

One of the requirements is to find a technique that allows the user to travel shortand long distances in a comfortable way. Having to use different techniques totravel short or long distances could lead to a worse experience at the end becauseusers would have to change techniques often.

4.2 Real users

This application aims to support planetary scientists in order to measure and findsignificant data on Mars using high-resolution 3D surface reconstructions.

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16 Chapter 4. Implementation of the locomotion techniques

This way, studying what is the technique that they find most comfortable comparedwith other is an important aspect of this project. Using the adequate locomotiontechnique can result in letting the geologists focus in other aspects while travelingor moving more accurately through the scene.

4.3 Tools

The tools needed for the study are the HTC Vive controllers and the head mountdevice (HMD). The HMD is used to watch the virtual environment, while the con-trollers are used to perform the different actions. The follow-up figure illustratedthe different names of the controller’s buttons.

Figure 4.1: HTC Vive controller layoutSource: https://forums.unrealengine.com/development-discussion/vr-ar-development/103602-unreal-button-mapping-names-for-oculus-touch/page2

4.4. Implementation 17

4.4 Implementation

This section describes in detail the more technical part of the study. For a betterunderstanding, each navigation technique has a different section. Additionally,there is a more general section that explains the implementation that applies to alltechniques, like the change to the final position of the user.

4.4.1 General implementation

There are two parts of the code that are applied equally in all the techniques: thepart of changing user’s position and the part of hovering the evaluation landmarks.The following sub sections describe each of them separately.

Changing user’s position

During the implementation of this study, there have been three different coordi-nate systems that have been working concurrently but have not been defined yet.Therefore, an understanding of how the spaces are related between each other isneeded, to have them all in the same origin and at the same scale. The three spacesused in the project are:

• Opc Space: this space is only used to translate the OPC from its originalposition to the origin, where all the other spaces have their origin as well. Wecall this spcace opcSpace.

• Annotation Space: space used to translate the items that we add to the scenelike flags, lines or drawings to our world. We refer to this space as annota-tionSpace.

• Working Space: it is the space that describes the movements that the user doeswith the controller/s. This space is updated at every frame and stores allthe changes applied in the scene by the controllers. We refer to this space asworkingSpace.

To see the changes applied by the controller to the scene and objects added, it isnecessary to combine the workingSpace with the two respective spaces separately.This space differentiation is important because all the objects that are in the scene(the opc and the annotation items) do not share the same origin and scale.

In addition to this, each coordinate system has two different variables: the ini-tial and the current variable. For the opcSpace and the annotationSpace, the initialvariable is static and it corresponds to the origin of their respective worlds. On theother hand, the initial variable of the workingSpace is updated every time that thetrigger is unpressed, in order to update the variable with the latest movements of


the controller and then apply them the next time a change is done.

This explanation from above has been extracted from the report of my internshipof Semester 9 [10]. This thesis could be considered as a continuation of the intern-ship. For this reason, the basic part of the code works equally.

Changing the user’s position is an aspect that had to be applied right after theuser decided to move. To do so, the logic action would be to apply the changesto the current position of the head mount device (HMD), because it is the cameraused by users to watch the virtual environment. Therefore, changing its positionwould mean changing what users see. However, the position of the HMD is re-lated to the sensors that are in the room and most of the times when users changeposition, their position in the real world does not change.

To actually change the users’ position, two steps have to be followed. First, get thenew position where users want to move in the annotationspace and then apply theinverse of this transform and multiply it by the initial variable of the workingspace.This way, instead of users moving to the new position, the virtual environmentmoves to the users until the HMD’s position is the same as the new position.

Hovering evaluation landmarks

To know when users were hovering or close enough to an evaluation landmark,meaning that they could proceed to move to the next one, the distance is com-puted.

The condition that had to be accomplished to compare the distance between theuser’s position and the evaluation landmarks is that they need to be in the samespace. Once this is accomplished, it is only needed to decide how close we wantusers to get to the evaluation mark to consider that they have got close enough. Inour case, 8 meters is considered close enough.

Figure 4.2 describes the storing of the variables needed to measure the distancebetween the controller and the corresponding landmark and the change of colorto notice users that they are close enough to the landmark and so that they canproceed to the next task: finding the "look at" landmark and pressing the triggerbutton (see Figure 4.1) to change its color to green.

In addition to that, the evaluation landmarks change their color when users getclose enough, so that they know they should proceed to the next landmark.


Figure 4.2: Pseudo code for the hovering of evaluation landmarks

4.4.2 Teleportation

Teleportation is one of the most common used locomotion techniques within thevirtual reality community. It consists of instantaneously moving the user to thepoint obtained from a ray that intersects with the plane and that starts in the con-troller.

To check an intersection two parameters are needed in our case: a k-d tree anda ray.

A k-d tree (k-dimensional tree) is a data structure used for organizing points ina k-dimensional space. In addition to that, a k-d tree helps speeding up ray inter-sections. The working virtual environment, called OPC, is composed of differentpatches and for each patch a k-d tree is loaded.

The other element needed to have an intersection is a ray. The ray will start at thecontroller’s position and will go forward and will be constantly checking againsteach k-d tree until it hits a k-d tree. The hit point will be retrieved when thereis a hit and therefore the intersection point will be provided. The pseudo code inFigure 4.3 describes how an intersection with a ray and the opcSpace is created.After finding an intersection, the pseudo code shows how to get the point of theopcSpace that has been intersected with the ray and where the final point of theray is transformed at the intersection point.


Figure 4.3: Pseudo code of teleportation technique

Finally, for a better visual feedback, a line is created out of the controller’s positionand the intersection point. This way, the potential teleportation point is showed.Figure 4.4 represents how the teleportation method is seen in the application.

Figure 4.4: Teleportation navigation method

To move to the intersected point, the user has to press the trigger button. Afterthat, Section 4.4.1 describes the change of the user’s position.

4.4.3 Drone navigation

When selecting drone mode as a navigation tool, a box appears in front of theuser’s position, referring to the drone. This box is the movable object that actslike a drone and that users will control around the environment to decide the newposition.


To move the drone, users have to press the trigger button. This action makesthe drone move at a constant speed. The direction followed by the drone is indi-cated by the main controller. This way, when the user holds the trigger button andpoints the controller forward, the drone will move forward. On the other hand, ifthe user points to the right, the drone will then change its trajectory to the right.The pseudo code of the implementation of this action is shown in Figure 4.5.

Figure 4.5: Pseudo code of drone movement

Lastly, a cylinder is also created in this mode. This object is attached to the droneand allows the user to spot where the drone is from a long distance. The cylinderis semitransparent so that the potentially occluded parts of the environment canstill be seen.

This mode offers the user the possibility to see from the drone’s position through asecond camera that is attached to the second controller, as seen in Figure 4.6. Thissmall camera follows the second controller’s movements: position and orientation.The direction towards where the camera is pointing is controlled by the main con-troller. This way, users have the sensation that the drone is making a turn whenthey change the orientation of the controller.

Unlike the teleportation technique, in order to move to a new position users haveto press the grip buttons. The reason for that change is that the trigger button isalready used to move the drone around. When users presses the grip buttons, theywill instantly move to the drone’s position in the scene.

4.4.4 World in Miniature

The third and last navigation technique consists of displaying a small overview ofthe environment that allows users to travel from their current position to anotherone through a mini map. In addition to the change of position, users can changetheir current orientation as well. Changing position and orientation at the sametime is useful in case they need to be facing a specific part of the scene that wouldneed a change of position and, afterwards, a change of orientation.


Figure 4.6: Drone navigation method

This technique can be divided in two different modes, which are represented dif-ferently in the menu: WIM and WIM Place Landmarks. First, the mode that showsthe mini map and the different landmarks that are in the environment. Secondly,the mode where users can actually change their current position.

When selecting the World in Miniature (WIM) technique, a mini map of the en-vironment appears attached to the main controller’s position. A scale-down of theactual virtual environment is applied to create the mini map. Furthermore, norotation is applied to the mini map. This way, users can actually walk around themap to orient themselves as they please.

The mini map shows three different features that are of great information for theuser: the user’s current position, the landmarks that they have to go and the land-marks that they have to look at, both represented with different colors. Figure 4.7depicts the mini map with these three features. As regards to the user’s currentposition, it is composed by two parts: a rectangle, representing the position, and acone, representing the orientation of the head mount device (HMD) to help usersknow where they are currently oriented in respect with the scene.

As soon as users decide to fix the mini map in a specific position, they have to callthe menu again and select the mode WIM Place Landmarks.


Figure 4.7: World in Miniature starting view, with the user position and evaluation landmarks

After fixing the mini map, users are now able to change their current position.To do so, they shall hover the object from the mini map representing themselves (arectangle and a cone in red). Once the user’s position object is hovered in the minimap a change of color will be applied to it, to give feedback to users.

To proceed with the change of position, users have to keep hovering and pressthe trigger button. At this point, a new figure appears in the mini map in a differ-ent color, representing the position and orientation that users had when pressingthe button. After this, the red rectangle and cone are attached to the controller’sposition and they also follow its orientation. The two user position can be seen inFigure 4.8. It is at this point when users can decide where to move in the scene.To do so, they have to unpress the trigger button and they will immediately betransported to that position in the real environment.

As additional feedback feature, a yellow landmark appears in the real world rep-resenting where users would move if they unpress the trigger button. Figure 4.9represents the mini map in the bottom right part of it as well as the potential userposition in yellow.

Unlike the other two navigation techniques, there are two different "worlds": theworld representing the mini map and the world representing the actual virtualenvironment. Therefore, changes that are applied in one world directly affect theother and the extrapolation between them has to be accurate. Otherwise, userscould be easily confused if their actions did not match both worlds.


Figure 4.8: User’s original position in cyan and current position in dark red

Figure 4.9: Mini map in the bottom right of the figure and yellow representation of future userposition

Chapter 5

Evaluation

5.1 Participants

A total of five participants (4 female and 1 male) volunteered to test the threedifferent locomotion techniques. The age of the participants varied from 27 to 35years old (mean 30 years old). The majority of the participants (80%) work or useVR devices on a daily basis and had experience with video games, playing 2-7times a week.

5.2 Environment

The virtual environment represents the Victoria Crater of Mars, created by recon-structed images obtained from orbiter images. This is one of the most famousdatasets of the Mars missions.

Due to the high similarity between the different bays and capes, there are notenough distinguishable locations in the environment which the user could go with-out needing any extra help. This is the reason why we added landmarks in theevaluation.

Regarding the landmarks added, there are two types of landmarks, each of themdistinguishable from each other with a different color and shape:

• Go-to Landmark: this type of landmarks, represented by a red rectangle in theenvironment are the objects which participants have to arrive by means ofthe different navigation techniques. As soon as they are close enough to thelandmark, this will trigger a change of its color to green.

• Look-at Landmark: when participants arrive to the go-to landmarks, they haveto spot the look-at landmark, represented with a blue cone. When users

25

26 Chapter 5. Evaluation

find the look-at landmark a trigger action is performed, meaning the look-atlandmark has been found, and changing its color to green.

With the use of these two different landmarks, users can use the different naviga-tion techniques by getting to the go-to landmark and their spatial orientation canbe tested by finding the look-at landmark.

To move to the next landmark, participants need to be close enough to the go-to landmark and find the corresponding look-at landmark. When this is done, thetwo landmarks will then turn green and two new landmarks (one of each type)will appear. A representation of this situation is shown in Figure 5.1, where thereare completed landmarks in green as well as the next landmarks that the partici-pant has to visit and look afterwards. Additionally, a message with the distance(in meters) to the next landmark can be seen constantly in the interface.

Figure 5.1: Completed landmarks (green) and next landmarks to go and look (red and blue)

5.3 Procedure

First, participants are introduced with a guide to the study. This introduction con-sists of teaching users how to use the three different techniques and to know whatkind of tasks they will have to perform. The guide lasts around 3 minutes (oneminute per technique).

5.4. Results 27

After completing the guide, participants fill in a demographics and VR experi-ence questionnaire and then they proceed with the testing of the first locomotiontechnique, randomly chosen. During each locomotion technique test, participantsare presented with the two first landmarks of the environment. Getting to thego-to landmark and finding the look-at landmark means the completion of a task.The evaluation of the navigation technique is completed when ten tasks have beenachieved.

After this, two different questionnaires are presented, consisting of the Kennedy-Lane simulator sickness questionnaire [13] (SSQ) and a likability questionnaire.

To conclude the experiment, when participants have used the three different lo-comotion techniques, they had to fill up a questionnaire gathering informationregarding the preference over each techniques. Overall, the experiment lasts 20 -30 minutes.

5.4 Results

Overall, the participants enjoyed the experience using the system. They consid-ered that they were successful using the system as well as that they could controlthe three different locomotion techniques. Figure 5.2 shows the average scoresobtained from the likability questionnaire that participants took after using eachnavigation method. The range from 1 (lowest score) to 5 (highest score) indicatesthat participants found the techniques easy to control and that the system was in-formative enough to complete all the tasks.

Figure 5.2: Scores of the likability questionnaire


As regards to the gathering of symptoms of motion sickness and disorientationparticipants took the SSQ after using each technique. A Friedman test compar-ing the results obtained from the three methods showed a statistically significantdifference between the three techniques (χ2(2)=8.49, p=0.0144). Post-hoc Wilcoxonsigned-rank tests with Bonferroni corrections applied yielded statistically signifi-cant differences between using the drone technique and the WIM technique (p =0.0215).

This difference can also be appreciated in Figure 5.3, where it can be seen thatresults are worse when users were using the drone technique unlike when usingthe WIM technique.

Figure 5.3: Simulator Sickness Questionnaire average scores

When it comes to finding a statistically significant difference between each vari-able the same post-hoc Wilcoxon signed rank test with Bonferroni correction isconducted. However, there is no statistically significant difference in this regardin any of the different variables. Despite not finding any significant difference,variables like general discomfort, eye strain, nausea, blurred vision, dizziness witheyes closed or stomach awareness could be possible candidates of showing a sta-tistically significant difference if more participants were evaluated.

Kennedy et al. divided the symptoms of the SSQ in three groups: nausea, ocu-lomotor and disorientation as well as a total score. The groups are formed bydifferent variables of the SSQ, that can be part of more than one group.

5.4. Results 29

Figure 5.4: SSQ scores in the three groups and total score

As it can be seen in Figure 5.4 the drone technique out-performs in all the groups,specially in the disorientation group. However, according to the users’ commentsteleportation was the technique causing more disorientation or confusion of theirposition after teleporting multiple times.

In addition to that, this navigation technique also stands out when it comes tothe feeling of nausea. On the other hand, the WIM technique has the lowest scoresin all the groups, confirming it was the most preferred technique by the users andthe most comfortable one, offering low levels of disorientation as well as cybersickness.

Users were asked in relation to their preferences over techniques at the end ofthe evaluation. In this regard, all the participants agreed that the WIM techniquewas the best to find the target because of the mini map representation, same forthe understanding of the user’s position. On the contrary, the worst navigationtechnique and the worst one to understand the user’s position was dominated byteleportation with a 60% and a 40% of drone technique according to participantsin a questionnaire about preference over techniques that taken at the end of theevaluation.

The WIM technique also dominates the comfort of use, with a 60% of the answersfrom the users, and a shared 20% of the answers to the remaining techniques.

Video recordings of the users using each technique suggest that WIM could possi-bly be the most efficient technique. Having the overview as interaction board and


having information such as the position of the go-to and look-at landmarks as wellas the user’s position and orientation helped users to quickly locate the look-atlandmark as soon as they reached the go-to landmark. Some users even changedtheir orientation in order to face the look-at landmark. In fact, users that noticedthis mentioned the positive impact it had compared to the other two techniques.Users that did not take advantage of this, did not have any problems in findingthe look-at landmark quickly, since they already knew their final orientation andwhere they had to look in order to find the blue cone.

During navigation, using the drone technique, participants also focused on otherparts of the environment during the process of getting to the target. For this rea-son, it was easy for them to orient and find the look-at landmark once they wereclose enough to the go-to landmark.

On the other hand, a slight difference can be seen when users used teleportation.They sometimes had to look around the scene to find the blue cone because theywere more focused on pointing and teleporting towards the go-to landmark andafter that they focused on finding the look-at landmark.

In other words, WIM and drone techniques potentially take the same time when itcomes to finding the look-at landmark. On the other hand, teleportation is slowerbecause users had to first orient themselves and then find the look-at landmark.

Chapter 6

Discussion

Having an environment with no significant landmarks in it leaded to having to addlandmarks so that users could navigate to them without any help. Two differentlandmarks have been added, as explained in Section 5.2: the go-to landmark (redrectangle) and the look-at landmark (blue cone).

A task consisted of first going to the go-to landmark and then finding the look-at landmark. The intention behind this procedure is to discover if users have tofocus mostly to using the navigation technique to get to the go-to landmark or ei-ther they can focus on the environment and the look-at landmark while navigating.

During the drone technique, users commented it was the most entertaining oneeven though it was the one that took them the most to complete due to the size ofthe environment and the fact that the speed was constant. For this reason, provid-ing different drone speeds to the user could be a solution. However, the interactionon how to change from one speed to another intuitively can be challenging. An-other option could be to not having a constant speed and changing the drone’sspeed depending on how pressed the trigger button was.

The fact that the drone technique got the worst scores in Figure 5.4 could pos-sibly be related to the amount of time it took the participants to complete thetasks. Users completed the tasks using the WIM and teleportation way faster thanwhen using the drone technique. This could explain why the nausea group is sig-nificantly higher in the drone technique than the two others. The nausea grouphas variables like general discomfort, nausea, difficulty concentrating or stomachawareness, which their averages were all the highest compared to the other tech-niques.

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32 Chapter 6. Discussion

The disorientation group in Figure 5.4 shows a big difference between the dronetechnique, which obtained worse scores than the two others. An explanation tothis could be related to the type of participants. Note that 80% of the users workor use VR on a daily basis, meaning that they could be used to the teleportationtechnique, being one of the most common locomotion techniques in professionalapplications and public installations, while the drone technique has not been im-plemented anywhere before.

The differences reflected in Figure 5.4 can also be seen separated by each symptomin Figure 5.3. It would be interesting then, to discover exactly what symptomshave a statistical significant difference between the different techniques. However,that is hard to get with only five participants and we can only get a trend of whatsymptoms could possibly have a statistically significant difference.

With 30 participants, more robust statistics could be generated. Perhaps, a sta-tistically significant difference could be found using a Friedman test and, if thep-value was lower than 0.05, a post-hoc Wilcoxon signed-rank test could tell uswhat techniques have a statistically significant difference.

Another topic of discussion is the scenario that has been used in the evaluation.As mentioned before, the similarity of the bays and caves of this scenario is high,which could also lead to a higher disorientation. Testing the navigation techniquesin a scenario with canyons or craters could lead to different results. In a scenariowith a lot of canyons, the drone technique could be a potential candidate to be themost efficient, enabling the users to move between the canyons freely and easilyunlike the two other techniques.

The scale of the environment is something to take into consideration when se-lecting the locomotion technique. In our case, where the environment is aboutone kilometer diagonally, results suggest that WIM works properly. Nevertheless,WIM might not be as good in a way smaller environment, where walking can bethe most efficient and natural option to move around. This is why it is interestingto test these techniques in environments of different scales.

Chapter 7

Conclusion and Future Work

There is no such definitive virtual reality navigation technique that works perfectlyin all the environments. Nonetheless, disorientation and motion sickness are as-pects to take into account when selecting a navigation technique regardless of thescenario.

In this study, three different locomotion techniques have been compared in a bigand similar virtual environment. Symptoms of orientation and motion sicknesshave been analysed in detail, discovering that the World in Miniature techniqueturns out to be the most efficient technique in such environments.

This study could also be the start of a continuation of Berger et al.’s study, thatfound out that the WIM technique reduced the feeling of motion sickness and dis-orientation in small environments. With the results obtained in this study, the samefindings might apply for bigger environments.Nonetheless, users felt comfortable using the two other techniques (teleportationand drone navigation), suggesting they could be useful in different scenarios.

Important factors to take into consideration for the selection of the appropriatelocomotion technique and for future studies are the scale of the environment andthe type of environment.

As part of a future work, more participants should conduct this study. A totalnumber of five participants only gives a trend of what could possibly be the finaloutcome of this study, but with this number of participants the results can not beconsidered statistically significant.

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Bibliography

[1] Laurenz Berger and Katrin Wolf. “WIM: Fast Locomotion in Virtual Realitywith Spatial Orientation Gain & without Motion Sickness”. In: Proceedingsof the 17th International Conference on Mobile and Ubiquitous Multimedia. 2018,pp. 19–24.

[2] Costas Boletsis. “The new era of virtual reality locomotion: a systematic lit-erature review of techniques and a proposed typology”. In: Multimodal Tech-nologies and Interaction 1.4 (2017), p. 24.

[3] Costas Boletsis and Jarl Erik Cedergren. “VR locomotion in the new era ofvirtual reality: an empirical comparison of prevalent techniques”. In: Ad-vances in Human-Computer Interaction 2019 (2019).

[4] Costas Boletsis, Jarl Erik Cedergren, and Stian Kongsvik. “HCI research invirtual reality: A discussion of problem-solving”. In: International Conferenceon Interfaces and Human Computer Interaction, IHCI 2017, Portugal, 21–23 July2017. 2017.

[5] Doug A Bowman and Larry F Hodges. “An evaluation of techniques forgrabbing and manipulating remote objects in immersive virtual environ-ments”. In: Proceedings of the 1997 symposium on Interactive 3D graphics. 1997,35–ff.

[6] Doug A Bowman, Donald B Johnson, and Larry F Hodges. “Testbed evalua-tion of virtual environment interaction techniques”. In: Presence: Teleoperators& Virtual Environments 10.1 (2001), pp. 75–95.

[7] Doug A Bowman et al. “An introduction to 3-D user interface design”. In:Presence: Teleoperators & Virtual Environments 10.1 (2001), pp. 96–108.

[8] Doug A Bowman et al. “Maintaining spatial orientation during travel in animmersive virtual environment”. In: Presence 8.6 (1999), pp. 618–631.

[9] Evren Bozgeyikli et al. “Point & teleport locomotion technique for virtualreality”. In: Proceedings of the 2016 Annual Symposium on Computer-HumanInteraction in Play. 2016, pp. 205–216.

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[10] Marc Domenech. “Internship at VRVis Zentrum fürVirtual Reality”. In: 2019(2019).

[11] MP Jacob Habgood et al. “Rapid, continuous movement between nodes asan accessible virtual reality locomotion technique”. In: 2018 IEEE Conferenceon Virtual Reality and 3D User Interfaces (VR). IEEE. 2018, pp. 371–378.

[12] Andras Kemeny et al. “New vr navigation techniques to reduce cybersick-ness”. In: Electronic Imaging 2017.3 (2017), pp. 48–53.

[13] Robert S Kennedy et al. “Simulator sickness questionnaire: An enhancedmethod for quantifying simulator sickness”. In: The international journal ofaviation psychology 3.3 (1993), pp. 203–220.

[14] Martin Kraus. “On the Preference for Travel by Steering in a Virtual RealityGame”. In: 2019 (2019).

[15] Eike Langbehn, Paul Lubos, and Frank Steinicke. “Evaluation of locomotiontechniques for room-scale vr: Joystick, teleportation, and redirected walk-ing”. In: Proceedings of the Virtual Reality International Conference-Laval Virtual.2018, pp. 1–9.

[16] Joseph J LaViola Jr. “A discussion of cybersickness in virtual environments”.In: ACM Sigchi Bulletin 32.1 (2000), pp. 47–56.

[17] Joseph J LaViola Jr et al. 3D user interfaces: theory and practice. Addison-WesleyProfessional, 2017.

[18] Dongsheng Lu. Virtual Reality sickness during immersion: An investigation ofpo-tential obstacles towards general accessibility of VR technology. 2016.

[19] Kyle Olszewski et al. “High-fidelity facial and speech animation for VRHMDs”. In: ACM Transactions on Graphics (TOG) 35.6 (2016), pp. 1–14.

[20] Randy Pausch et al. “Navigation and locomotion in virtual worlds via flightinto hand-held miniatures”. In: Proceedings of the 22nd annual conference onComputer graphics and interactive techniques. 1995, pp. 399–400.

[21] Beatriz Sousa Santos et al. “Head-mounted display versus desktop for 3Dnavigation in virtual reality: a user study”. In: Multimedia tools and applications41.1 (2009), p. 161.

[22] Richard Stoakley, Matthew J Conway, and Randy Pausch. “Virtual realityon a WIM: interactive worlds in miniature”. In: Proceedings of the SIGCHIconference on Human factors in computing systems. 1995, pp. 265–272.

[23] VRVis zentrum für virtual reality und visualisierung forschungs-gmbh. https://www.vrvis.at/.

https://www.vrvis.at/

https://www.vrvis.at/

Appendix A

Appendix

A.1 Logs of the implementation

A.1.1 Week 1(10th - 14th February)

• Research state of the art: what kind of techniques are rellevant to study,specially in evironments similar like ours.

• Think of innovative navigation methods

• Navigation methods to consider: WIM, Drone control center, walking, GoogleEarth method, Landmarks & Fix-Scale, Waltz of Wizard (game) teleportationmethod

A.1.2 Week 2(17th - 21st February)

• Refactor internship code in order to reuse parts of it.

• Annotation part of the internship code removed.

• Menu is re used as well.

• Implementation of adding landmarks in the scene

• Implementation of World in Miniature technique - display a smaller minimap in the screen

• Start implementation of placing landmarks in mini map

A.1.3 Week 3(24th - 28th February)

• Implementation of adding landmarks in mini map done.

• Implementation of user’s position in mini map

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38 Appendix A. Appendix

• Landmarks are positioned in the mini map and the real world

• mini map orientation on controller started to be implemented

A.1.4 Week 4(2nd - 6th March)

• Implementation of laser pointer without intersection

• Landmarks move together in the mini map and the real world with the con-troller according to controller’s position

• Drone control center implementation: drone moves according to controller’sorientation

• Start implementation of second camera that will show what the drone isseeing

• Drone center updates user position when finished: user will go to the drone’sposition if the grip button is pressed

• Camera follows the drone

A.1.5 Week 5(9th - 13th March)

• Drone cyllinder implemented

• Addition of cone in the mini map that displays the user’s HMD orientation

• Implementation of change of user’s position in the mini map when hoveringit in the mini map.

• Translation of user’s position from mini map to real world implemented.When user changes its own position in the mini map, the changes are appliedin the real world as well.

• Implementation of showing the initial position of the user in the mini mapwhen changing its position.

A.1.6 Week 6(16th - 20th March)

• new user orientation in the mini map is taken into account

• drone camera orientation is now according to hmd orientation

• OPC and landmarks displayed together in the second camera

• New cylinder transportation technique started to implement

A.1. Logs of the implementation 39

• when in cylinder mode, opc disappears so that the user thinks he is in aroom.

• add landmarks in cylinder mode

• Basic teleportation technique implemented. To teleport the user presses theback button.

• Border applied in the second camera when in drone mode to differentiatefrom the background

A.1.7 Week 7(23rd - 27th March)

• move second camera when hovering and pressing back button

• Implementation of changing user position in mini map with main controller(it was done with second controller before) so that it is more intuitive forusers

• Rotation to drone controller by the HMD implemented

• initial user position and orientation in mini map implemented

• hover and move position of second screen improved

• drone mode with second screen attached to controller

A.1.8 Week 8(30th March - 3rd April)

• code refactoring

• second screen shift trafo implemented

• drone improvements from first round of user feedback

A.1.9 Week 9(6th - 10th April)

• Landmarks orientation fixed to be vertical

• Change orientation of HMD to controller’s when changing user position inwim

• Evaluation task started: target appears one by one and the user has to hoverthem so that next one appears



• Set position of evaluation landmarks

• Landmarks appear one at a time

• Change color when user is hovering the landmarks or is close enough

• Wim and drone evaluation landmarks working

• wim evaluation done

• First pilot study package created

• Orientation teleportation in wim working


• fix wim opc position

• drone is bigger now

• second screen attached to second controller

• visual feedback when hovering in wim

• border of second camera attached to controller

• rudimentary teleportation implemented

• distance to landmark set as text in the application

• kd-tree loading and saving implemented

• implementation of intersection of ray and opc working

• orientation in teleportation mode working

• line controller to intersection in teleportation mode working


• second camera rotation same as controller

• look evaluation landmark when pressing trigger button of second controller

• mark main controller

A.2. Demographics Survey 41

A.1.13 Week 13(4th - 8th May)

• screen in second controller smaller

• position of second screen further from controller

• order of appearance of landmarks is randomized

• distance properly computed to landmark. Instead of euclidean distance, theminimum distance to the surface

• cones instead of rectangles for the look at landmarks

• main controller cone (pointer) used as an arrow to change the user positionin wim

• evaluation landmarks are semi transparent

• user study program

A.1.14 Week 14(11th - 13th May)

• workaround for cosmos vive

A.2 Demographics Survey

• How old are you?

• What is your sex?

– Female

– Male

– Prefer not to say

• How much experience do you have with VR?

– I have worked with it before

– I work with, or use, VR on a daily basis

– I have tried it multiple times before

– I have tried it a couple of times before

– I have tried it once before

– I have no experience in VR

• How often do you play video games?


– Once a year or less

– Once a month

– Once a week

– 2-3 times a week


– Daily

• How often do you use mapping and location services (for example, GoogleMaps)?

– Once a year or less

– Once a month

– Once a week



– Daily

A.3 Likert Questionnaire

The questions in this questionnaire had a scale from 1 (not at all) to 5 (very much).

• Navigation technique used

– Teleportation

– Drone navigation

– WIM (mini map)

• Did you enjoy your experience with the system?

• Were you successful using the system?

• Were you able to control the system?

• Is the information provided by the system clear?

• Did you feel discomfort during your experience with the system?

A.4. Simulator Sickness Questionnaire 43

A.4 Simulator Sickness Questionnaire

The questions in this questionnaire had all the same answers. Users had to choosebetween none, slight, moderate and severe according to what they experienced inthe evaluation.

• Navigation technique used

– Teleportation


– WIM (mini map)

• General discomfort

• Fatigue

• Headache

• Eye strain

• Difficulty focusing

• Salivation increasing

• Sweating

• Nausea

• Difficulty concentrating

• Fullness of head

• Blurred vision

• Dizziness with eyes open

• Dizziness with eyes closed

• Vertigo

• Stomach awareness

• Burping


A.5 Preference over techniques questionnaire

• Which navigation technique was best to find the target?

– Teleportation


– WIM (mini map)

• Why?

• Which navigation technique was worst to find the target?

– Teleportation


– WIM (mini map)

• Why?

• Which navigation technique was best to move to the target?

– Teleportation


– WIM (mini map)

• Why?

• Which navigation technique was worst to move to the target?

– Teleportation


– WIM (mini map)

• Why?

• Which navigation technique felt most comfortable?

– Teleportation


– WIM (mini map)

• Why?

• Which navigation technique felt least comfortable?

– Teleportation

A.5. Preference over techniques questionnaire 45


– WIM (mini map)

• Why?

• Which navigation technique was best to understand your own?

– Teleportation


– WIM (mini map)

• Why?

• Which navigation technique was worst to understand your own?

– Teleportation


– WIM (mini map)

• Why?

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